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Membrane Particle Interaction in Triaxial Testing: FEM-DEM Coupling and CT Imaging Insights
Citation Link: https://doi.org/10.15480/882.13718
Publikationstyp
Conference Presentation
Date Issued
2024-09-27
Sprache
English
Author(s)
DCS-Computing
TORE-DOI
Citation
5th Aspherix & CFDEM Conference (2024)
Contribution to Conference
Publisher DOI
This conference presentation supplements the abstract submitted to the 5th Aspherix CFDEMcoupling conference. That has taken place from 25.09.24 - 27.09.24 in Vienna, Austria.
This conference contribution presents recent advances in implementing a FEM-DEM solver into Aspherix. Implementing this FEM-DEM coupling aims to account for membrane particle interaction in numerical simulations, i.e., encountered in triaxial testing, a standard test in soil mechanics, where the DEM accounts for particle motion and the FEM for the membrane deformation. Furthermore, we showcase specific image processing techniques based on 4D (3D+time) in situ X-ray computed tomography (CT) experiments to set up and validate such numerical simulations.
Miniaturized triaxial experiments have been performed on a cylindrical (height 20 mm; diameter 11 mm) dry granular particle assembly. Here, a specimen made of 1 mm glass beads is examined. Axial deformation is exerted onto the specimen, leading to a consecutive shear deformation. At each 1 % of axial strain (here: engineering strain with ε=Δl/l_0) the experiment is halted to acquire a tomography of the current state. A total of 15 % of strain is applied.
On the one hand, the acquired image data of the initial particle configuration is processed to act as input for the numerical simulation. On the other hand, sophisticated image analysis based on an image correlation procedure tracks individual particles throughout the experiment solely based on the acquired image data, giving displacement vectors for each particle (see figure below). This data is complemented by externally measured axial force, which describes the examined specimen's shear resistance. Both force measurements and displacement vectors act as a validation for the numerical simulation.
Finally, current limitations of the implementation are discussed, such as available element types for modelling the membrane, and an outlook for further improvements is given.
This conference contribution presents recent advances in implementing a FEM-DEM solver into Aspherix. Implementing this FEM-DEM coupling aims to account for membrane particle interaction in numerical simulations, i.e., encountered in triaxial testing, a standard test in soil mechanics, where the DEM accounts for particle motion and the FEM for the membrane deformation. Furthermore, we showcase specific image processing techniques based on 4D (3D+time) in situ X-ray computed tomography (CT) experiments to set up and validate such numerical simulations.
Miniaturized triaxial experiments have been performed on a cylindrical (height 20 mm; diameter 11 mm) dry granular particle assembly. Here, a specimen made of 1 mm glass beads is examined. Axial deformation is exerted onto the specimen, leading to a consecutive shear deformation. At each 1 % of axial strain (here: engineering strain with ε=Δl/l_0) the experiment is halted to acquire a tomography of the current state. A total of 15 % of strain is applied.
On the one hand, the acquired image data of the initial particle configuration is processed to act as input for the numerical simulation. On the other hand, sophisticated image analysis based on an image correlation procedure tracks individual particles throughout the experiment solely based on the acquired image data, giving displacement vectors for each particle (see figure below). This data is complemented by externally measured axial force, which describes the examined specimen's shear resistance. Both force measurements and displacement vectors act as a validation for the numerical simulation.
Finally, current limitations of the implementation are discussed, such as available element types for modelling the membrane, and an outlook for further improvements is given.
Subjects
FEM-DEM coupling
X-ray computed tomography
Triaxial testing
DDC Class
620: Engineering
Publication version
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